Greg Aldering may have a day job at the Lawrence Berkeley Lab shining light on “dark energy” and working on the Supernova Cosmology Project with fellow scientists including Sarl Perlmutter, co-winner of the 2011 Nobel Prize in Physics.

But Tuesday afternoon he was hanging out with neighbors in the El Cerrito hills demonstrating a technique for viewing a rare “,” which is when Venus passes across the face of the Sun.

Of course, you can’t look at the Sun safely with your naked eyes, but with a telescope he made as a teenager and a beat-up cardboard filebox lid with a piece of white paper taped to it, Aldering showed neighbors a reflection of the planet appearing as a little black shadow moving slowly across a glowing white disk.

A special thanks to resident Denise Sangster for alerting us to the gathering and sending us the accompanying photos.

P.S. If you missed Tuesday’s transit of Venus, there will be a bit of a wait until the next one – in 2117.